de Kloet, RS; de Kloet SR (2005). "The evolution of the spindlin gene in birds: Sequence analysis of an intron of the spindlin W and Z gene reveals four major divisions of the Psittaciformes". Molecular Phylogenetics and Evolution36 (3): 706–721. PMID16099384. doi:10.1016/j.ympev.2005.03.013.
Schweizer, M.; Seehausen O, Güntert M and Hertwig ST (2009). "The evolutionary diversification of parrots supports a taxon pulse model with multiple trans-oceanic dispersal events and local radiations". Molecular Phylogenetics and Evolution54 (3): 984–94. PMID19699808. doi:10.1016/j.ympev.2009.08.021.
de Kloet, RS; de Kloet SR (2005). "The evolution of the spindlin gene in birds: Sequence analysis of an intron of the spindlin W and Z gene reveals four major divisions of the Psittaciformes". Molecular Phylogenetics and Evolution36 (3): 706–721. PMID16099384. doi:10.1016/j.ympev.2005.03.013.
Schweizer, M.; Seehausen O, Güntert M and Hertwig ST (2009). "The evolutionary diversification of parrots supports a taxon pulse model with multiple trans-oceanic dispersal events and local radiations". Molecular Phylogenetics and Evolution54 (3): 984–94. PMID19699808. doi:10.1016/j.ympev.2009.08.021.